For correct diagnosis of various diseases, e.g. cancer, biopsies are often taken. This can either be performed via a lumen of an endoscope or via needle biopsies. In order to find the correct position where the biopsy has to be taken, various imaging modalities are used such as X-ray, Magnetic Resonance Imaging (MRI) and ultrasound. For example in most of the cases of prostate cancer the biopsy is guided by ultrasound. Although helpful, these methods of guidance are far from optimal. The resolution is limited and, furthermore, these imaging modalities can in most cases not discriminate between benign and malignant tissue.
In order to improve the biopsy procedure direct inspection of the biopsy position, prior biopsy, is required. A way to achieve this direct inspection is by microscopic inspection at the specific position. This requires a miniaturised confocal microscope coupled to an optical fiber probe. However, this system has the drawback that its scanning properties strongly depends on the mechanical properties of the optical guide.
A way to avoid this dependency is described in U.S. Pat. No. 6,967,772 where a scanning fiber system based on an electrically operated tuning fork with an attached fiber is disclosed. The mechanical properties of the scanning system described by the US patent are determined by the tuning fork and not by the fiber. However a disadvantage of this system is that it requires a significant amount of space, due to the dimension of the tuning fork, hampering the downscaling of the system. Furthermore, since the driving frequency of the fiber is in this system the resonance frequency of the tuning fork, non resonant scanning is not possible.
In summary, none of previously disclosed fiber scanning systems solves the problem of how to provide a scanning optical guide system in which the mechanical properties of the scanning system is not determined by the optical guide, without compromising the downscaling of the system.
Hence, an improved scanning system which allows for resonant and non resosonat scanning, which allows for downscaling and in which the mechanical properties are independent from the optical guide used, would be advantageous.